Ok, this could get confusing because I have to sperate issues on two seperate sites. That's why I created two seperate posts. In my earlier post, the very last thing I mentioned that I had to roll back the website to dnn 5 because that site generates a lot of traffic. If you go to http://temp.nprailfest.com/shoponline.aspx you can see the button issue. I know the detail page is broken, but it's just a temp site. However, the regular storefront page shows my issue, hover over one of the product images and you'll see.
The issue with http://buzzsmarine.com/Storefront.aspx is when you add something to your cart, it has no skin, just a blank white page. I have verified this using the dotnetnuke skin as well as my custom skin. I'm guessing you haven't had a ton of extensive testing on dnn 6 with this so if I can be of any help, please just let me know.